1. Field of the Invention
The present invention relates to an anesthetic delivery system and in particular to a system adapted to re-use anesthetic that remains unabsorbed by a patient from a previously inhaled anesthetic dose.
2. Description of the Prior Art
It is know from U.S. Pat. No. 4,015,599 to provide an anesthetic delivery system having a delivery unit that houses a carbon dioxide absorber and a reversible action anesthetic adsorption filter arranged in series and in gaseous communication with a gas flow passage that provides a flow path for gas through the unit via the carbon dioxide absorber and the anesthetic adsorption filter. A charge of a gas-forming anesthetic is also provided as part of the system, pre-loaded into the anesthetic adsorption filter.
In use, the unit of the known anesthetic delivery system is disposed in gas flow connection with a tubing circuit of a so-called “closed” inhalation anesthesia system. The unit is intended to be used in a manner such that exhaled breathing gas within the tubing circuit passes first through the carbon dioxide absorber and then through the adsorption filter to collect. This anesthetic gas is then supplied into the tubing circuit for inhalation by the patient, together with fresh breathing gas that is added after the unit to compensate for the gas that was consumed.